The ALIAS Trial (Albumin In Acute Stroke) is a randomized, double-blind, placebo-controlled, multicenter, Phase III clinical trial of high-dose human albumin (ALB) therapy for neuroprotection in acute ischemic stroke. The Trial builds upon extensive preclinical evidence that high-dose ALB is markedly neuro- protective;and our ongoing NIH-funded Phase I ALB Dose-Escalation and Safety Clinical Trial, which has completed the fifth of the six pre-specified ALB dose-tiers (total of 70 subjects) and has shown that the higher doses can be safely administered without ALB-related toxicity and with strong suggestions of efficacy. Significantly, dose-tier V (1.71 g/kg) falls well within the per-kg dose-range of 1.25-2.50 g/kg shown in preclinical studies to be highly protective. The primary aim of the ALIAS Phase III Trial is to ascertain whether high-dose ALB therapy, compared to saline-placebo, will increase the proportion of favorable outcome in subjects with acute ischemic stroke. To this end, we propose to conduct two separate but concurrently implemented randomized, double-blinded trials of ALB therapy in patients with acute ischemic stroke whose baseline NIH Stroke Scale Score (NIHSSS) is 6 or greater and who can be treated with ALB within 5 hours of stroke-onset. The two trials will be carried out in two cohorts: one that receives standard-of-care treatment with i.v. tPA;and one that does not receive tPA. Decision regarding tPA therapy is based on the local best standard of care. The primary hypothesis will be tested separately in each cohort. Favorable outcome is defined as either an NIHSSS of 0 or 1, or a modified Rankin Score (mRS) of 0 or 1, or both, measured at 3 months from randomization. The trials will incorporate interim analyses, and a maximum of 1,800 subjects will be recruited at 40 clinical sites in the U.S. and Canada. The ALIAS Trial affords the unique opportunity to apply a preclinically highly effective strategy to treat stroke using a dose and timing that closely replicate the experimental setting in which efficacy was shown.